16. No order may be made under paragraph 12, and no application may be made under paragraph 13 or 15, while an appeal against the relevant order is pending.
17.—(1) Subject to sub-paragraph (2), where a court proposes to exercise its powers under this Part, otherwise than on the application of the offender, the court—
(a)shall summon him to appear before the court; and
(b)if he does not appear in answer to the summons, may issue a warrant for his arrest;
and the court shall not amend a relevant order under this Part unless the offender expresses his willingness to comply with the requirements of the order as amended.
(2) This paragraph shall not apply to an order cancelling a requirement of a relevant order or reducing the period of any requirement, or substituting a new petty sessions district or a new place for the one specified in the relevant order.
18.—(1) On the making under this Part of an order amending a relevant order, the clerk to the court shall forthwith—
(a)if the order amends the relevant order otherwise than by substituting a new petty sessions district or a new place for the one specified in the relevant order, give copies of the amending order to the responsible officer;
(b)if the order amends the relevant order in the manner excepted by paragraph (a), send to the clerk of petty sessions for the new petty sessions district—
(i)copies of the amending order; and
(ii)such documents and information relating to the case as he considers likely to be of assistance to a court acting for that district in exercising its functions in relation to the order;
and in a case falling within paragraph (b) the clerk of petty sessions for that district shall give copies of the amending order to the responsible officer.
(2) A responsible officer to whom in accordance with sub-paragraph (1) copies of an order are given shall give a copy to the offender and to the person in charge of any institution in which the offender is or was required by the order to reside.
(3) Where a probation order is in force in respect of an offender under the age of 21 years who is subsequently committed to a training school under the [1968 c. 34 (N.I.).] Children and Young Persons Act (Northern Ireland) 1968 or to a young offenders centre, the probation officer who supervises the case shall send such documents and information relating to the case as he considers likely to be of assistance to the managers of the school or, as the case may be, the governor of the young offenders centre.